The crowd of anti–Gang of Eight activists that marched through Washington, D. C., on Monday encompassed a fairly broad swath of political factions. But the tea-party presence was substantial — and it wasn’t surprising. The Senate’s recently passed bill, which includes a path to legalization for illegal immigrants, has galvanized conservative grassroots activists, and tea-party leaders nationwide are working to organize the opposition. If Monday’s protesters are any indicator, they’ve got one top target: Senator Marco Rubio.

Jack Oliver of Floridians for Immigration Enforcement, who carried a bag full of “AMNISTIA!” buttons featuring the face of the Florida senator wearing a sombrero, told me that he and others hope former congressman Allen West will primary Rubio when he likely runs for reelection in 2016. To them, his status as a tea-party darling is finished.

Don Smith, a conservative talk-show host who does public relations for the Black American Leadership Alliance and helped publicize the event, tells me that the Gang of Eight’s bill has “absolutely” reinvigorated many activists. He estimates that between 80 and 90 percent of self-identified tea-party activists oppose the bill. “We’ve gone back to actually standing, taking marches,” he says. “Things kind of died down a little bit [in recent years], but this has definitely brought people out.” He guessed that more than 5,000 people attended the event.

Andy Ramirez, the president and founder of the Law Enforcement Officers Advocates Council, says he noticed a new tone at the rally that suggests an important change in the way grassroots activists approach immigration. For the first time in a decade, he tells me, members of the conservative grassroots are itching to primary Republicans over their stances on the immigration issue. He also said the crowd was thinking in terms of how to elect an anti-amnesty president in 2016. Attendees, he recalls, said things like, “Imagine a ticket with Ted Cruz and Jeff Sessions, or imagine a ticket with Jeff Sessions and Allen West.”

Ramirez adds that grassroots activists are also eyeing House speaker John Boehner as a potential primary target.

Ken Crow of TeaPartyCommunity.com agrees. He says that more than a few are eyeing the speaker. “Boehner already knows that if he brings this to the floor in any shape, form, or fashion, he’ll be unemployed,” Crow says. “I’ve made that perfectly clear. I will do everything in my power to unseat that man . . . We view him as, for lack of a better word, a marshmallow. He’s weak.”

Boehner and Rubio, though, aren’t the only targets. Crow says Senator Lindsey Graham of South Carolina, who is up for reelection next year, is also on anti-amnesty crowd’s radar, and that some groups hope conservative Nancy Mace, a business woman and the first female graduate of The Citadel, will challenge him.

As far as organization goes, the Tea Party’s anti-amnesty wing is growing far beyond the capital march. D. A. King of the Dustin Inman Society says that a coalition of more than 50 conservative groups in Georgia called the Georgia Immigration Enforcement Coalition has sent a letter to each of the state’s nine Republican congressmen pledging to find and support primary opponents if they support any kind of amnesty for illegal immigrants. “If there is a Republican who votes for any kind of legalization, he will be in deep trouble,” King says, though he added that he doesn’t expect any of the state’s Republican representatives to support such a measure.

Rubio, Graham, Boehner, and other pro-reform leaders should take note: The Tea Party, long focused on fiscal issues, has added immigration to its ambit. Activists are marching on the capital’s streets once again, and getting ready to drive supporters of legalization out of office. “Give it about six months, and you’re going to see how well organized some people are,” Ramirez says.